Tactile buttons on a mobile device are typically placed on outer exposed surfaces for ease of use and ergonomics reasons. These buttons typically protrude from the device surface so that they are easy to displace with a finger to a point of switch activation. To provide a high-quality button press experience, the gap between the button and a switch actuator must be very tightly controlled during the manufacturing process. If the gap is too large, the button will rock from side-to-side during button press, resulting in an undesirable feel to the user. If the gap is too small (e.g., interference), the tactile feel of the switch is undesirable due to the small amount of button travel. If the gap is too large or too small, the product yield decreases due to repair or discard of the devices.
Some solutions focus on tightly controlling dimensions of the switch assembly during manufacturing via short tolerance chains, custom adjustment of each of the switch assemblies using shims of various sizes, accepting poor yield, or accepting (and selling) devices with poor quality tactile feel. Each of these solutions are undesirable. For example, tightly controlling the dimensions is expensive and often infeasible due to device architecture constraints. Custom adjustment of each of the switch assemblies is a labor intensive effort and logistically difficult, resulting in higher costs for the user. Yield loss is also expensive, while poor quality tactile feel results in a had user experience and loss of sales.
Further, impact events such as an accidental drop may result in a loss of tactility and/or functionality of the switch. For example, materials inside the switch may be permanently deformed or cracked. To prevent this, some existing designs for the switch assemblies rely only on inherent energy absorption characteristics of the device chassis. When subject to the full force of impact during accidental drops, such existing switch assemblies and buttons are often damaged, adversely affecting customer satisfaction.